1. Field of the Invention
The present invention relates to entry door frames and more particularly to entry door frames having reinforcement members provided therein.
2. Description of the Prior Art
Door frames have been utilized in the building products industry for a long time. For many years door frames were virtually always constructed of wood. Although wood was a generally acceptable material for such products, the use of wood resulted in several disadvantages. Wood is subject to impact damage, i.e., denting and splintering upon contact. Further, over time wood may shrink, swell, bow, warp, crack or rot. Deterioration of wood commonly resulted from contact with moist, salt laden air as well as from contact with pollution and air borne chemicals. And although structurally rigid, wood is relatively heavy as compared to other materials. Moreover, in order to appear aesthetically appealing, wood must typically be painted and/or stained initially and then repainted periodically. The paint itself can fade, streak, flake or peel, resulting in an unattractive appearance.
More recently, synthetic materials have been utilized in connection with door frames. Polyvinyl chloride ("PVC") has been the most commonly utilized synthetic material. In general, synthetic materials have shown superior qualities of wood when utilized in door frames. For example, PVC has very favorable long term weatherability and UV performance. PVC can be extruded to have a finished appearance, thus requiring no painting and/or finishing. Also, PVC is waterproof and is therefore resistant to water damage and to damage resulting from moist, salt laden air, pollution and air borne chemicals. Further, PVC is generally resistant to impact damage and can withstand mechanical stress and strain. PVC is also impervious to insects. However, PVC displays limited heat resistance and, therefore, has limited applicability in areas having very hot climates.
Even more recently, other synthetic materials have been utilized in the building construction industry for window and door profiles. In particular, acrylonitrile butadiene styrene ("ABS") has been utilized by itself or with a co-extruded surface protection coating of acrylate styrene acrylonitrile ("ASA"). The ABS/ASA combination displays many of the beneficial features that are shown by PVC. Further, the ABS/ASA combination has higher impact resistance and reduced weight per volume than PVC. However, as with all synthetic materials, the ABS/ASA combination is susceptible to heat damage.
Safety is a primary consideration in the home building products industry. For example, homes having an integral garage are required by many local ordinances to have an internal metal door separating the garage from the remainder of the home. The function of the metal door is to assist in preventing fire from traveling from the garage into the home. Due to synthetic building materials being susceptible to fire damage, door frames for entry doors that are made of synthetic material have been known to melt during fires. When the door frame melts, the door falls away from the home leaving an opening for air currents to enter the home, fueling the fire.
Despite the superiority of synthetic material over wood in many areas, many purchasers of home building products elect not to use synthetic materials in door frames. One reason why synthetic material door frames are bypassed is a perception by the consumer that the door frame constructed of synthetic material is not sufficiently substantial (i.e., sturdy, strong, etc.). The ABS/ASA combination is particularly prone to this criticism due to its having a lower weight per volume than PVC. One solution is to provide the door frame with a solid door profile. This results in the use of much more synthetic material than is necessary, thus raising costs.
Therefore, it would be advantageous to develop an improved door frame design which utilizes synthetic materials. Such a door frame design should result in increased structural rigidity, a feeling of substantiality and an increased barrier to the spread of flames through the door frame. Such a door frame design should use a minimum amount of synthetic material in order to minimize material costs.
Furthermore, door frames in the prior art have typically utilized heads and sills that are fabricated from a number of different members. Typically, sections of the head and sill are joined together, end to end, in series. The jambs and mullions are then attached to sections of the head and sections of the sill. Thus, door frame structures have typically been fabricated in the industry from a number of individual pieces which are nailed, screwed or otherwise joined together. It would further be advantageous, therefore, to develop an improved door frame design which utilizes heads and sills which are fabricated of single, continuous members rather than a number of individual members joined together in series.